High churn is creating stress on the market, Miller said. "You have people scrambling, they want to be here in the city. There is job growth, there is a lot going on here. But the jobs that are needed to be filled are by people who can't afford to pay the rent."

Developments in Queens and Brooklyn are becoming condos instead of rental apartments, Miller said, adding to the inventory shortage. "Land prices have risen so much ... the math doesn't work for rental anymore."

Low inventory also means less incentives for renters. "Concessions being offered by landlords, like free rent, have nearly evaporated."

And it doesn't look like price relief is coming anytime soon.

"I don't see the narrative changing in the foreseeable future," Miller said. "It's a very complex problem; a city can't grow if new entrants to the city can't afford to live there."